diff --git a/sys/conf/NOTES b/sys/conf/NOTES index 5baa306c99db..5cc146eb6b49 100644 --- a/sys/conf/NOTES +++ b/sys/conf/NOTES @@ -2958,6 +2958,7 @@ options SC_RENDER_DEBUG # syscons rendering debugging options VFS_BIO_DEBUG # VFS buffer I/O debugging options KSTACK_MAX_PAGES=32 # Maximum pages to give the kernel stack +options KSTACK_USAGE_PROF # Adaptec Array Controller driver options options AAC_DEBUG # Debugging levels: diff --git a/sys/conf/options b/sys/conf/options index 42113c35bd3e..83375217f89a 100644 --- a/sys/conf/options +++ b/sys/conf/options @@ -136,6 +136,7 @@ KDTRACE_FRAME opt_kdtrace.h KN_HASHSIZE opt_kqueue.h KSTACK_MAX_PAGES KSTACK_PAGES +KSTACK_USAGE_PROF KTRACE KTRACE_REQUEST_POOL opt_ktrace.h LIBICONV diff --git a/sys/kern/kern_intr.c b/sys/kern/kern_intr.c index 6e9a4e8e48d2..d6de6111bb1f 100644 --- a/sys/kern/kern_intr.c +++ b/sys/kern/kern_intr.c @@ -28,6 +28,7 @@ __FBSDID("$FreeBSD$"); #include "opt_ddb.h" +#include "opt_kstack_usage_prof.h" #include #include @@ -1396,6 +1397,10 @@ intr_event_handle(struct intr_event *ie, struct trapframe *frame) td = curthread; +#ifdef KSTACK_USAGE_PROF + intr_prof_stack_use(td, frame); +#endif + /* An interrupt with no event or handlers is a stray interrupt. */ if (ie == NULL || TAILQ_EMPTY(&ie->ie_handlers)) return (EINVAL); diff --git a/sys/sys/systm.h b/sys/sys/systm.h index 0f2732c06601..c484b7b3374a 100644 --- a/sys/sys/systm.h +++ b/sys/sys/systm.h @@ -443,4 +443,6 @@ bitcount16(uint32_t x) return (x); } +void intr_prof_stack_use(struct thread *td, struct trapframe *frame); + #endif /* !_SYS_SYSTM_H_ */ diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c index 61c003bec8b7..c9ee890824a5 100644 --- a/sys/vm/vm_glue.c +++ b/sys/vm/vm_glue.c @@ -62,6 +62,7 @@ __FBSDID("$FreeBSD$"); #include "opt_vm.h" #include "opt_kstack_pages.h" #include "opt_kstack_max_pages.h" +#include "opt_kstack_usage_prof.h" #include #include @@ -98,6 +99,8 @@ __FBSDID("$FreeBSD$"); #include #include +#include + #ifndef NO_SWAPPING static int swapout(struct proc *); static void swapclear(struct proc *); @@ -486,6 +489,52 @@ kstack_cache_init(void *nulll) SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL); +#ifdef KSTACK_USAGE_PROF +/* + * Track maximum stack used by a thread in kernel. + */ +static int max_kstack_used; + +SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD, + &max_kstack_used, 0, + "Maxiumum stack depth used by a thread in kernel"); + +void +intr_prof_stack_use(struct thread *td, struct trapframe *frame) +{ + vm_offset_t stack_top; + vm_offset_t current; + int used, prev_used; + + /* + * Testing for interrupted kernel mode isn't strictly + * needed. It optimizes the execution, since interrupts from + * usermode will have only the trap frame on the stack. + */ + if (TRAPF_USERMODE(frame)) + return; + + stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE; + current = (vm_offset_t)(uintptr_t)&stack_top; + + /* + * Try to detect if interrupt is using kernel thread stack. + * Hardware could use a dedicated stack for interrupt handling. + */ + if (stack_top <= current || current < td->td_kstack) + return; + + used = stack_top - current; + for (;;) { + prev_used = max_kstack_used; + if (prev_used >= used) + break; + if (atomic_cmpset_int(&max_kstack_used, prev_used, used)) + break; + } +} +#endif /* KSTACK_USAGE_PROF */ + #ifndef NO_SWAPPING /* * Allow a thread's kernel stack to be paged out.